A conventional infusion set as shown in FIG. 5 includes a needle N mounted on a holding tube T, a delivery tube D connected between the holding tube T and an infusion bottle or bag (not shown ) such as filled with medical liquid or blood for intravenous injection or blood transfusion, a wing portion W disposed on two opposite side portions of the holding tube T for adhering the infusion set on a patient's skin, and a sleeve S for inserting a used needle N into the sleeve S for its safety disposal.
However, the sleeve S has a very small diameter for inserting the needle N therein and the used needle N may still stick or prick someone's hand H such as of a nurse, a doctor or a hospital housekeeper of waste disposal when inserting the needle N into the very small sleeve S as illustrated in FIG. 5.